Newly elected school board Chair Richard Mammen said Wednesday evening that he's planning to step down after one term as board member so that he can give board duties precedence over campaigning.

Mammen, 63, said he was planning to e-mail supporters the news some 24 hours after he was elected chair Tuesday night on a 7-2 vote.

Mammen's departure from the field leaves a citywide board seat open this fall. Former Chair Alberto Monserrate said he's not yet ready to announce whether he'll seek another term representing a Nokomis area district. The Minneapolis DFL part has scheduled its precinct caucuses for Feb. 4, giving potential candidates to replace either incumbent little time to organize after they disclose their plans.

The development has the potential to foster a re-run on a city stage the electoral rivalry between forces supporting unionized teachers and those advocating for what they call school reform that played out in a lakes area board district in 2012.

Rebecca Gagnon, the other citywide board member with an expiring term this year has declared her candidacy. Dick Velner and Doug Mann have declared their citywide candidacies but neither has demonstrated much strength in previous bids.

One candidate considering a run for either Mammen's or Monserrate's seat is Nelson Inz, The 44-year-old teacher at a St, Paul charter high school said he's been considering a run for several years. He lives in the Regina neighborhood. He said he would seek and abide by DFL endorsement if he runs.

Mammen said he waited to make his announcement until after he knew if he would be chair, and it was possible that he would have sought another term had he not won the seat He was the DFL's only endorsee for citywide school board in 2010, and set a school campaign fundraising record that since has been broken. But he was one of a crew of four board members who drew some ire before their swearing in for signing a letter on union letterhead urging resolution of a teacher labor contract dispute.

Mammen said that to do the job of chair, he needs to eschew the campaign jobs of raising money and pounding lawn signs. "To be effective, I need to focus on the role of chair," he said.

He's a dozen years older than his next oldest board colleague, so his departure will leave the board with just one baby boomer member. He has boyhood links to former Hennepin County Commissioner Mark Andrew, and supported his unsuccessful bid for mayor, which was seen by some as a last hurrah for a passing generation of DFL pols and supporters.

Whoever runs as an incumbent this year can point to the board's track record of getting district finances on firmer ground by ending the practice of unbalanced budgets that ate into district reserves. That helped to improve the district's credit rating. School enrollment is growing again, after a decade of decline. Incumbents also plan to have a revamped strategic plan in place by the time they face voters.

But challengers will be able to point to the painfully slow pace of improvement in the district's biggest problem, its yawning achievement gap.